1. Field of the Invention
The present invention relates to a method and apparatus for converting digital content metadata received external to a network into digital content metadata peculiar to the network and a network system using the same. Particularly, the present invention relates to a method and apparatus for allowing TV-Anytime information to be used in a Universal Plug and Play (UPnP) content directory service (CDS) and a network system using the same. More particularly, the present invention relates to a method and apparatus for converting digital content metadata for allowing UPnP devices to utilize TV-Anytime information through a UPnP CDS and a network system using the same.
2. Description of the Related Art
If a viewer wishes to watch a desired broadcast program through a television (TV), the viewer should be able to watch a desired TV program without regard to a broadcast schedule. Presently, it is possible to overcome some of the time limitations by using the reservation recording function of a video cassette recorder (VCR). Such a case, however, is inconvenient in that the viewer must check the program schedule and make reservations for the desired programs one by one. With the development of digital technologies such as moving picture compression technology including MPEG (Moving Picture Experts Group), large-capacity HDD (Hard Disk Drive), video editing technology and the Internet, a personal video recorder (PVR) for home use, which has a large-capacity storage device, has recently been brought onto the market.
A user of the PVR can watch a desired TV program at a desired time and receive a variety of additional services. The PVR is a system for allowing a broadcast program input to a computer through various channels such as cable, satellite broadcasting and digital TV to be stored in the HDD of a computer by means of moving picture compression technology. The PVR has convenient search and play functions, excellent sound/image quality, and an ability to simultaneously perform the play and record functions, which cannot be obtained with audio and video cassette recorders. The PVR includes a TV tuner, operating software, a modem and a hard drive, and thus, a user can select and record a desired program at a desired time through the Internet by using a remote control.
To accomplish these services, content producers, communication and broadcasting companies, service providers, and electric appliance companies gathered and established the civil standard organization called TV-Anytime forum on September 1999. The TV-Anytime forum is comprised of several working groups for business models, system technology, metadata, content referencing, and content protection/management, to perform the standardization. As of June 2002, “1st Draft of Metadata Specification SP003v1.3” was announced. More detailed information is available from the web site, www.tv-anytime.org.
The Universal Plug & Play (UPnP) forum was established on Oct. 18, 1999 and has defined “UPnP device and service descriptions” (originally called device control protocols or DCPs) according to a common device architecture contributed by Microsoft. The goals of the UPnP forum are to enable the emergence of easily connected devices and to simplify the implementation of networks in the home and corporate environments. The UPnP forum achieves these goals by defining and publishing UPnP device and service descriptions built on open Internet-based communication standards.
The UPnP forum's web site, www.upnp.org, is a central repository for schemas that have been developed and standardized by the UPnP forum. In addition, the web site contains the device architecture document, templates for device and service descriptions, and guidelines for device and service description design. Through the use of UPnP, devices can be automatically and dynamically connected to a network, secure an Internet Protocol (IP) address, deliver functions, and check the presence and function of other devices. Thus, a genuine network with a zero configuration can be implemented. Devices further strengthen a peer-to-peer networking function by continuously communicating directly with the other devices.
The coverage of UPnP is very broad to such an extent that the UPnP can be applied to new fields as well as existing fields such as home automation, printing and imaging, audio/video entertainment, kitchenware, and automobile networks. Further, since UPnP uses standard TCP/IP (Transmission Control Protocol/Internet Protocol), it can be freely integrated into existing networks. UPnP supports communication between a control point and a device. Network media, TCP/IP protocol and HTTP (HyperText Transfer Protocol) provide basic network connectivity and addressing schemes. On the basis of the open standard Internet-based protocol, UPnP defines a series of HTTP servers for processing search, description, control, event, and presentation. UPnP-based devices can receive a variety of content through UPnP CDS. The UPnP CDS stores information about content stored in other locations as well as in itself, so that they can easily use relevant content.
FIG. 1 is a view showing an environment where TV-Anytime and UPnP CDS are used.
Devices shown in FIG. 1 include a device 10 with only a UPnP CDS 11, a device 20 with only a module 21 for processing TV-Anytime metadata, and a device 30 with both a module 31 for processing TV-Anytime metadata and a UPnP CDS 32. These devices can receive content through the Internet, public broadcasting, cable broadcasting, satellite broadcasting or the like.
FIGS. 2a and 2b are diagrams schematically showing the hierarchical structure of metadata for current UPnP CDS.
Data stored by UPnP CDS are roughly classified into two metadata classes, i.e. an item class 110 and a container class 120. In general, the item class 110 represents multimedia data existing in a single unit, e.g. a video file or a music file, and the container class 120 is a unit including the items and can represent a folder album etc. All these classes are inherited from a class called an object 100.
The item class 110 includes a plurality of subclasses that includes a videoItem class 112 for representing image data. The videoItem class 112 also includes a plurality of subclasses that includes a movie class 114 for representing video data where images are mainly contained, a videoBroadcast class 116 for representing broadcasting data, and the like.
The container class 120 includes a subclass such as the genre class 122 for representing a genre, which in turn includes its own subclass such as the movieGenre class 124 that is a collection of items where movies are collected according to genres.
Each class of UPnP CDS has a property for representing its own characteristics, which is shown in Table 1. The subclasses inherit the properties of the upper classes in the same way as the concept of object orientation.
TABLE 1Class namePropertiesObjectid, parentID, title, creator, res, class,restricted, writeStatusItemrefIDVideoItemgenre, longDescription, producer, rating, actor,director, description, publisher, language, relationMoviestorageMedium, DVDRegionCode, channelName,scheduledStartTime, scheduledEndTimeVideoBroadcasticon, region, channelNrContainerchildCount, createClass, searchClass, searchable
A UPnP CDS shows its own metadata in an XML format when a UPnP device requests the metadata. An example of item information, which the UPnP CDS returns to the UPnP device using UPnP CDS, is given as follows:
  <DIDL-Lite xmlns:dc=“http://purl.org/dc/elements/1.1/” xmlns:upnp=“urn:schemas-upnp-org:metadata-1-0/upnp/” xmlns=“urn:schemas-upnp-org:metadata-1-0/DIDL-Lite/”> <item id=“10” parentID=“4” restricted=“false”>  <dc:title>Desert Rose</dc:title>  <dc:creator>Sting</dc:creator>  <upnp:class>object.item.audioItem.musicTrack</upnp:class>  <res     protocolInfo=“http-get:*:audio/x-ms-wma:*”size=“50000”>   http://10.0.0.1/getcontent.asp?id=10  </res> </item>  </DIDL-Lite>
FIG. 3 shows the configuration of TV-Anytime metadata.
TV-Anytime metadata 200 are expressed in an XML format and have an element called <TVAMain> in its top layer. Further, below this element, there exists information 210 on a program, information 220 on program location or service, information 230 on a consumer or user, information 240 on segments corresponding to pieces of the program, and the like. Below the program information 210, there exists information 211 on the program itself, information 212 on a group corresponding to a unit for binding a plurality of programs, information 213 on people (e.g., actors or directors) or organization related to the program, and information 214 on program reviews. Below the program location or service information 220, there exists information 221 on the service, information 222 on the actual location of the program, and the like. Below the consumer information 230, there exists information 231 on consumer's preferences or tastes, information 232 on the consumer's access records, and the like. Finally, information 241 on the segments and the like are arranged below the segmentation information 240.
UPnP uses UPnP CDS so that a common interface is provided when UPnP devices intend to obtain content information. Further, the UPnP devices use content metadata obtained from UPnP CDS in order to provide the consumer with services. The metadata forming UPnP CDS represents information on the multimedia data stored in UPnP devices 10 and 30. A process through which UPnP CDS obtains the multimedia data information is not clearly stated in the UPnP device and service descriptions. TV-Anytime defines a standard for service, technology and tools for use in a multimedia platform based on the storage media used. Content dealt with in TV-Anytime include radio programs, audio tracks, MPEG4 objects, images and music as well as TV broadcasting programs. TV-Anytime allows various services to be provided to a consumer using various metadata such as the title and synopsis of a program.
The metadata of TV-Anytime are delivered to the devices 20 and 30 through broadcast signals or via the Internet. The devices process and use the received metadata to generate an electronic program guide (EPG). To access the program that the consumer selects while viewing the EPG, the devices find out the location of a selected program through a method known as “location resolution” using a unique identifier, which is called a Content Reference Identifier (CRID) which is assigned to each selected program, and obtains the broadcast content from the location information so that the consumer can watch or record the selected program.
However, TV-Anytime and UPnP CDS, which provide the consumer with metadata, manage metadata that are not compatible with each other. Such a structure has the following problems. First, since UPnP devices capable of accessing only UPnP CDS cannot use the metadata provided by TV-Anytime, the needs of a consumer who wants to access all the metadata cannot be satisfied. Further, if the devices needed for content metadata should support UPnP CDS and TV-Anytime in order to solve this problem, a heavy burden will be imposed on the devices.
UPnP CDS provides a movie class 114, a videoBroadcast class 116 and the like to represent broadcast content, but the properties of these classes are very weak. Thus, only very limited information is delivered to a user. Due to these problems, devices are divided into a device supporting TV-Anytime and a device supporting UPnP CDS. Additionally, there exist devices that support both TV-Anytime and UPnP CDS but provide the consumer with irrelevant information. As a result, this causes an inconvenience to the consumer. Moreover, the inconvenience of using such devices is further increased due to the dual accessibility of the metadata.